When remounting ext4 from ro to rw, currently it allows its transition, even if ext4_commit_super() returns EIO. Even worse thing is, after that, fs/buffer complains buffer dirty bits like:
Call trace: [<ffffff9750c259dc>] mark_buffer_dirty+0x184/0x1a4 [<ffffff9750cb398c>] __ext4_handle_dirty_super+0x4c/0xfc [<ffffff9750c7a9fc>] ext4_file_open+0x154/0x1c0 [<ffffff9750bea51c>] do_dentry_open+0x114/0x2d0 [<ffffff9750bea75c>] vfs_open+0x5c/0x94 [<ffffff9750bf879c>] path_openat+0x668/0xfe8 [<ffffff9750bf8088>] do_filp_open+0x74/0x120 [<ffffff9750beac98>] do_sys_open+0x148/0x254 [<ffffff9750beade0>] SyS_openat+0x10/0x18 [<ffffff9750a83ab0>] el0_svc_naked+0x24/0x28 EXT4-fs (dm-1): previous I/O error to superblock detected Buffer I/O error on dev dm-1, logical block 0, lost sync page write EXT4-fs (dm-1): re-mounted. Opts: (null) Buffer I/O error on dev dm-1, logical block 80, lost async page write Cc: "Theodore Ts'o" <[email protected]> Cc: Andreas Dilger <[email protected]> Cc: [email protected] Cc: Jaegeuk Kim <[email protected]> Signed-off-by: Jaegeuk Kim <[email protected]> --- Change log from v2: - fix missing goto condition fs/ext4/super.c | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 185f7e61f4cf..32cf16c33cba 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2116,12 +2116,12 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es, int read_only) { struct ext4_sb_info *sbi = EXT4_SB(sb); - int res = 0; + int err = 0; if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) { ext4_msg(sb, KERN_ERR, "revision level too high, " "forcing read-only mode"); - res = SB_RDONLY; + err = -EROFS; } if (read_only) goto done; @@ -2154,7 +2154,7 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es, if (sbi->s_journal) ext4_set_feature_journal_needs_recovery(sb); - ext4_commit_super(sb, 1); + err = ext4_commit_super(sb, 1); done: if (test_opt(sb, DEBUG)) printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, " @@ -2166,7 +2166,7 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es, sbi->s_mount_opt, sbi->s_mount_opt2); cleancache_init_fs(sb); - return res; + return err; } int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup) @@ -4760,11 +4760,7 @@ static int ext4_commit_super(struct super_block *sb, int sync) unlock_buffer(sbh); error = __sync_dirty_buffer(sbh, REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0)); - if (error) - return error; - - error = buffer_write_io_error(sbh); - if (error) { + if (buffer_write_io_error(sbh)) { ext4_msg(sb, KERN_ERR, "I/O error while writing " "superblock"); clear_buffer_write_io_error(sbh); @@ -5165,8 +5161,12 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) if (sbi->s_journal) ext4_clear_journal_err(sb, es); sbi->s_mount_state = le16_to_cpu(es->s_state); - if (!ext4_setup_super(sb, es, 0)) - sb->s_flags &= ~SB_RDONLY; + + err = ext4_setup_super(sb, es, 0); + if (err) + goto restore_opts; + + sb->s_flags &= ~SB_RDONLY; if (ext4_has_feature_mmp(sb)) if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block))) { @@ -5190,8 +5190,11 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) } ext4_setup_system_zone(sb); - if (sbi->s_journal == NULL && !(old_sb_flags & SB_RDONLY)) - ext4_commit_super(sb, 1); + if (sbi->s_journal == NULL && !(old_sb_flags & SB_RDONLY)) { + err = ext4_commit_super(sb, 1); + if (err) + goto restore_opts; + } #ifdef CONFIG_QUOTA /* Release old quota file names */ -- 2.17.0.484.g0c8726318c-goog
